purescript - Unify record types with overlapping fields

Question

I have the following code:

workWithImportantField :: forall fields. { importantField :: Int | fields } -> Input
workWithImportantField = ...

workWithImportantField $ 
maybe { importantField: 1 } identity (Just { importantField: 1, fieldIDontCareAbout: "whatever" })

This doesn't compile because the first record doesn't have the fieldIDontCareAbout. However, I'm perfectly fine if it unifies into forall fields. { importantField :: Int | fields } so it gets passed into workWithImportantField. How would I go about doing that?

I've tried adding type annotations to various places (first record, second record, the whole expression) without success. I can always replace identity with unsafeCoerce, but I would like a type-safe solution. I can also manually pick out the fields I need by replacing identity with { importantField } -> { importantField }, but that doesn't look nice.

Answer 1

Replacing identity with pick found at Record.Extra "throws away" fieldIDontCareAbout from the second record so the types unify.